Gene test determines ideal dose of blood thinner

Atlanta, February 19: The researchers have developed a new way to give people the proper dose of warfarin, a leading blood thinner, as the wrong amount of the dose can be dangerous.

Warfarin is used worldwide to prevent dangerous blood clots that can lead to heart attacks, strokes or even death. Every year, about 4 million Americans with certain heart conditions or other risk factors take warfarin.

It is very hard to predict the ideal dose because it varies for person to person. Correct dose of the drug is very important because too much of it can lead to bleeding and too little can develop life-threatening clots.

In the new study, the researchers from nine different countries collected the information from about 5,700 people worldwide on stable dosages of warfarin. They studied the demographic information like age, gender and race plus CYP2C9 and VKORC1 variants and warfarin dosages.

After some trial and error, the researchers found that the prediction of dosagewas more accurate when they included genetic information. As a result, the researchers developed a way to use genetic information from patients that could help doctors predict the proper warfarin doses for each patient.

National Institute of Health (NIH) will soon launch a randomized clinical trial to test the gene study's results in the United States. The researchers supported by NIH will study the effects of genetic information to determine the initial warfarin dose for 1,200 participants of different ethnic groups and backgrounds at twelve clinical sites.

Raynard S. Kington, M.D., Ph.D., acting NIH director said, "In these investigations, NIH-funded basic research and clinical trials are working hand in hand to improve the care of the millions of patients on warfarin therapy; More broadly, these efforts showcase NIH's firm commitment to building a future of personalized medicine—a future in which doctors will be able to prescribe the optimal dosage of medicine for each patient right from the start."

"With growing evidence on how certain genesdefine affect the way individual patients respond to warfarin, we are now ready to move forward with a major clinical trial to test these strategies in patients who are starting warfarin therapy," said Elizabeth G. Nabel, M.D., director of NHLBI, which is supporting the new study.

The study is funded by the National Institutes of Health and several international medical organizations. It was published today in The New England Journal of Medicine.